The present invention relates to a disk apparatus such as a mini disk (MD), a compact disk (CD) or a digital video disk (DVD) for converting an analog signal such as an audio signal into a digital signal to perform recording and reproducing to a disk-shaped record medium (disk).
Recently, MD players for converting an analog signal of audio into a digital signal to record it in a magneto-optical disk have rapidly become prevalent as a recording and reproducing apparatus of an audio signal substitute for analog cassette players.
FIG. 1 is a block diagram showing a basic circuit configuration of such MD players.
An output of an optical pickup 3 for detecting information from a magneto-optical disk (hereinafter called xe2x80x9cmini diskxe2x80x9d) 1 rotated and driven by a spindle motor 2 is introduced to an address decoder 5, an EFM.ACIRC encoder/decoder 6 and a digital servo processor 7 through an RF amplifier 4, and an output of the address decoder 5 is introduced to the EFM.ACIRC encoder/decoder 6. Also, an output of the EFM.ACIRC encoder/decoder 6 is introduced to a magnetic head 9 for recording through a REC head driver 8. The EFM.ACIRC encoder/decoder 6 performs processing for separating signals of 16 bits with 8 bits to convert the 8 bits into 14 bits according to an error-correcting system by EFM modulation or ACIRC.
Also, the output of the EFM.ACIRC encoder/decoder 6 is introduced to the digital servo processor 7, and an output of the digital servo processor 7 is introduced to the spindle motor 2 and a thread motor 11 through a driver 10. The thread motor 11 is a motor for moving the whole of the optical pickup 3 or the magnetic head 9 for recording in a radial direction of the mini disk 1.
Also, the EFM.ACIRC encoder/decoder 6 is bidirectionally connected to a memory controller 12, and the memory controller 12 is bidirectionally connected to an ATRAC encoder/decoder 13, and the ATRAC encoder/decoder 13 is bidirectionally connected to an AD/DA converter 14 having an input terminal 15a and an output terminal 15b of analog audio.
Memory (D-RAM) 17 acting as a data buffer for preventing dropouts due to vibrations is connected to the memory controller 12. The memory controller 12 performs processing for once storing digital signals reproduced from the mini disk 1 in the D-RAM 17 and then sequentially taking out the digital signals and outputting them to the ATRAC encoder/decoder 13. Also, the ATRAC encoder/decoder 13 performs data compression or expanding of the compressed data by high efficient encoding processing referred to as ATRAC.
Each of these EFM-ACIRC encoder/decoder 6, digital servo processor 7, memory controller 12 and ATRAC encoder/decoder 13 is bidirectionally connected to an MPU 20 for performing operational control of the entire apparatus, and the MPU 20 has a configuration bidirectionally connected to a host CPU 30 which is a key controller. The MPU 20 receives various commands sent from the host CPU 30 and executes each processing according to the received commands.
Incidentally, a sampling rate converter which is connected to the ATRAC encoder/decoder 13 and directly performs digital signals or input and output terminals of the digital signals are omitted in FIG. 1.
FIG. 2 shows a data record layout of the mini disk 1. In a recordable MD, a Lead-in area including TOC, a UTOC area, a program area (digital signal recording area), and a Lead-out area are formed from the inner circumferential side toward the outer circumferential side of the disk, and the UTOC area and the program area are set as a recordable area. A laser power necessary in recording, a recordable area, and an address of UTOC are recorded in the TOC area. Also, part information of tracks (music) is recorded in the UTOC area, and each of the part information comprises a starting address and an ending address of the part, a track mode, and a link pointer. The link pointer indicates the starting address of the continuous part. For example, when one track (music) is divided into a part 1, a part 3 and a part 5, and is recorded in this order, a link pointer included in part information of the part 1 indicates a starting address of the part 3, and a link pointer included in part information of the part 3 indicates a starting address of the part 5.
Next, reproducing operations in the MD player constructed as shown above will be described.
When reproduction is started, the MPU 20 controls the digital servo processor 7 to control rotation of the mini disk 1 and movement of the optical pickup 3, and reads TOC information and UTOC information (index information) from the mini disk 1, and preserves this read UTOC information in the D-RAM 17 via the RF amplifier 4, the EFM.ACIRC encoder/decoder 6 and the memory controller 12.
Then, in order to acquire reproducing track information, the MPU 20 controls the memory controller 12 to acquire track pointer information of the UTOC, and acquires part information (hereinafter also called xe2x80x9cpart descriptorxe2x80x9d) of the UTOC corresponding to the acquired track pointer.
Here, when the track to be reproduced is divided into the part 1, the part 3 and the part 5 as described above, the MPU 20 acquires contents of a part descriptor corresponding to the first part 1 via the memory controller 12 and starts reproduction according to the acquired contents (a starting address, an ending address, a track mode and a link pointer). That is, the MPU 20 controls the digital servo processor 7 to move the optical pickup 3 to a target address (a starting address) and controls the EFM.ACIRC encoder/decoder to start the reproduction. The reproduced digital signal is amplified by the RF amplifier 4 and decoding processing such as EFM demodulation or error correction processing is performed by the EFM.ACIRC encoder/decoder 6 and then, the signal is once stored in the D-RAM 17 via the memory controller 12 and is again read at proper timing, and expanding of compression data is performed by the ATRAC encoder/decoder 13 and thereafter, the data is converted into an analog signal by the AD/DA converter 14 and is outputted from the analog audio output terminal 15b. 
In this manner, when the reproduction of the part 1 nears the end, the MPU 20 acquires part information to be next reproduced from information of the link pointer included in part information of the part 1 (the link pointer in this case indicates a starting address of the part 3), and acquires contents of a part descriptor corresponding to the next part 3 from the D-RAM 17 via the memory controller 12. Then, reproduction is continued according to the acquired contents (a starting address, an ending address, a track mode and a link pointer). In like manner, when the reproduction of the part 3 nears the end, the MPU 20 acquires part information to be next reproduced from information of the link pointer included in part information of the part 3 (the link pointer in this case indicates a starting address of the part 5), and acquires contents of a part descriptor corresponding to the next part 5 from the D-RAM 17 via the memory controller 12. Then, reproduction is continued according to the acquired contents (a starting address, an ending address, a track mode and a link pointer). Subsequently, when reproduction is performed to the ending address included in the part information of the part 5, the reproduction of the track (music) is completed.
In the conventional MD player thus, when operating the reproduction, it is constructed so that the MPU 20 acquires the part information in the UTOC information stored in the D-RAM 17 via the memory controller 12 and controls reproduction operations according to the acquired part information. Also, it is constructed so that the memory controller 12 reproduces the digital signal while continuously repeating the processing for sequentially buffering the digital signal read from the mini disk 1 in the D-RAM 17 and also sequentially decoding the buffered area at proper timing.
Such a buffering method using a storage medium such as the D-RAM 17 is conventionally performed and is disclosed in, for example, the Unexamined Japanese Patent Application Nos. Sho57-125439 or Hei9-222958 (JP-Patent No. 2853639).
By the way, in such a buffering method, as described above, the digital signal is reproduced while continuously repeating the processing for sequentially buffering the digital signal read from the mini disk 1 in the D-RAM 17 and also sequentially decoding the buffered area at proper timing. That is, a buffer area after decoding is constructed so as to be overwritten at the next buffering. As a result of that, even when it is considered that a user again wishes to reproduce the contents reproduced shortly previously, the contents does not already remain in the D-RAM 17, so that there was a problem that a reading must be again made from the mini disk 1 to perform reproduction.
Also, there is conventionally a function of A-B repeat, and this function is a function for preserving only an address of an A point and an address of a B point to perform repeat reproduction of an interval between the preserved addresses. As a result of that, for example, when a difference in phrases of a start and an end of music wishes to be listened and compared, access to the beginning of the portion must be repeated and there was a problem that operations become troublesome. Further, since an interval address of the A point and the B point is held to perform buffering again, it takes some time before a seek is completed and a starting address is detected, so that there was a problem that the interval becomes a no sound section.
The invention is invented to solve such problems, and it is an object of the invention to provide a disk apparatus constructed so that data of an overwrite inhibiting area can be reproduced anytime with a simple operation by providing an area for inhibiting overwriting in a buffer area.
In order to solve the problems, a disk apparatus of the invention is characterized in that the disk apparatus has reproducing control means for reproducing a digital signal while continuously repeating processing for sequentially buffering the digital signal read from a disk in a storage medium and also sequentially decoding the buffered area at proper timing in a normal reproducing mode, and comprises directive means for directing overwrite inhibiting of the storage medium, and the reproducing control means sets a predetermined area in a buffer area of the storage medium to an overwrite inhibiting area when the overwrite inhibiting is directed by operating the directive means and executes the normal reproducing mode while jumping this overwrite inhibiting area. As a result of this, the overwrite inhibiting area is secured in the buffer area of the storage medium used for the buffering in reproducing the digital signal, so that data stored in this overwrite inhibiting area can be easily reproduced anytime.
Also, the disk apparatus of the invention is characterized in that in the configuration, when the overwrite inhibiting is directed by operating the directive means, the reproducing control means sets an area between the next section of a buffer section in which buffering is completed at that point in time and a predetermined section to an overwrite inhibiting area. In other words, a user operates the directive means only once and thereby, the beginning and end of the overwrite inhibiting area are automatically determined and a simple operation can be provided for the user.
Further, the disk apparatus of the invention is characterized in that in each of the configuration, directive means for directing a special reproducing mode for reproducing the overwrite inhibiting area of the storage medium is included and the reproducing control means reproduces the overwrite inhibiting area once or repeatedly reproduces the area two or more times when the special reproducing mode is directed by operating the directive means. In other words, the data of the overwrite inhibiting area can be instantly reproduced by a simple operation of only operating the directive means.
Furthermore, the disk apparatus of the invention is characterized in that in the configuration, the reproducing control means executes the normal reproducing mode again from the buffer section of the time before executing the special reproducing mode after the special reproducing mode is executed and the overwrite inhibiting area is reproduced once or repeatedly reproduced two or more times. As a result of this, switching between the normal reproducing mode and the special reproducing mode can be done smoothly.
Moreover, the disk apparatus of the invention is characterized in that in each of the configuration, the overwrite inhibiting area can be set to plural portions in the buffer area of the storage medium. As a result of this, access to the beginning of phrases of the plural portions can be easily obtained without waiting time.
In addition, the disk apparatus of the invention is characterized in that in each of the configuration, the disk is a mini disk and the storage medium is D-RAM and a buffer section of the storage medium is a sector unit (one sector=64 msec). As a result of this, for example, when contents of foreign languages such as English conversation are reproduced, a repeat of one sentence can be done, and a repeat of one bar can be done in reproduction of music.